Housing for filter element; filter element; methods of use and making

ABSTRACT

A filter assembly includes a filter head and filter cartridge. The filter cartridge includes a housing and element. The housing includes a can with an open mouth. An interface ring is secured to the can adjacent to the open mouth. The outer ring surface is against the inner wall of the can. The ring wall is angled between the first and second ends greater than one degree and less than 6 degrees. Methods of filtering and making the housing are provided.

This application is a continuing application of U.S. patent applicationSer. No. 15/532,024, filed May 31, 2017, which is a National Stageapplication of PCT International Patent application No.PCT/US2015/066161, filed Dec. 16, 2015, which claims priority to U.S.Provisional patent application Ser. No. 62/093,729, filed Dec. 18, 2014,which applications are incorporated herein by reference. To the extentappropriate, a claim of priority is made to each of the above disclosedapplications.

TECHNICAL FIELD

This disclosure relates to filters. In particular, this disclosurerelates to a filter having an interface ring secured to a housing of thefilter and methods for making the filter.

BACKGROUND

Filters are needed for many different applications. For example, filterscan be used on engines to purify liquid, such as fuel or oil. Filterscan be used on engines for purifying air to be used in combustion.Filters can also be used on generators or various industrialapplications. For example, filters can be used for various gases,including propane gas. In these and other applications, it is importantthat the filter does not have any leaks allowing the liquid or gas toescape.

Improvements in filter designs are desirable, in particular to preventleaking.

SUMMARY

In accordance with principles of this disclosure, a housing for a filterelement is provided. The housing includes a can having a wallsurrounding an interior volume and an open mouth. The can wall has aninner wall surface in communication with the interior volume. Aninterface ring is secured to the can adjacent to the open mouth. Theinterface ring has a ring wall with first and second opposite ends, anouter ring surface, and an inner ring surface. The inner ring surfacecan be threaded, although other connection means are also contemplated.The outer ring surface is against the inner wall of the can. The ringwall is angled between the first and second ends greater than one degreeand less than 6 degrees.

A seal member can be at the open mouth to form a seal with a filterhead, and a filter head is secured to the housing.

The housing is seal member free between the interface ring and the canwall.

The interface ring will be self-supporting within the can.

The interface ring can have a beveled surface from the first end at theouter ring surface and extending to the inner ring surface.

The beveled surface can be at an angle of at least 40 degrees.

The beveled surface can be at an angle of no greater than 70 degrees.

In some implementations, the can has a section folded over the interfacering at the open mouth.

In some embodiments, the can has a section folded over and against thebeveled surface.

Preferably, the can has no more than a single fold.

In preferred implementations, the can has a closed end opposite of themouth.

In preferred embodiments, the can wall is shoulder-free at the secondend of the ring wall.

In many implementations, the can wall will be completely shoulder-free.

The ring wall can be angled between the first and second ends less than5 degrees.

The ring wall can be angled between the first and second ends at least1.5 degrees.

The ring wall can be angled between the first and second ends less than4 degrees.

The ring wall can be angled between the first and second ends between1.5 degrees and 4 degrees.

The outer ring surface will be against the inner wall of the can andwill be adhesive-free.

The interface ring will be secured to the can and be free of welds.

The can wall will have a cross-sectional thickness of about 0.6-1.5 mm,for example, about 1.1 mm. The can is made of pressed steel in one ormore embodiments.

In further aspects, a filter cartridge is provided including a housing,as variously characterized herein, and a filter element operably mountedin the interior volume of the can/housing.

The filter element can be non-removably mounted in the housing.

The filter element can be removable and replaceable in the housing.

The cartridge can be constructed and arranged to have a burst pressureof at least 1700 psig.

In further aspects, a filter assembly is provided. The filter assemblyincludes a filter head having a threaded connection portion and a filtercartridge, as variously characterized herein, threadably attached by theinterface ring to the threaded connection portion.

A method of filtering is provided. The method includes providing afilter assembly including a filter head and filter cartridge having ahousing; the assembly includes an inlet arrangement, outlet arrangement,and filter media; directing fluid into the housing through the inletarrangement, filtering the fluid by directing the fluid through themedia, and directing the fluid out of the housing through the outletarrangement; and wherein the burst pressure of the filter housing is atleast 1700 psig where the filter housing has a wall thickness of atleast 1.1 mm.

The method can include providing a housing as variously characterizedherein.

A method of making a housing for a filter element is provided. Themethod can include providing a can having a wall surrounding an interiorvolume and an open mouth surrounded by a rim. The can wall can have aninner wall surface in communication with the interior volume. The methodincludes pressing an interface ring into the interior volume of the canthrough the open mouth. The interface ring has a ring wall with firstand second opposite ends, an outer ring surface, and an inner ringsurface. The inner ring surface can be threaded, although otherconnection means are possible. The outer ring surface is against theinner wall of the can. The ring wall is angled between the first andsecond ends greater than one degree and less than 6 degrees. The methodincludes the step of pressing the rim of the can against the first endof the interface ring to fold the can against the interface ring.

The method can further include orienting a seal member on the folded rimof the can. In the method, the housing can be made to have any of thefeatures as variously characterized herein.

It is noted that not all the specific features described herein need tobe incorporated in an arrangement for the arrangement to have someselected advantage according to the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of one embodiment of a filter assemblyconstructed in accordance with principles of this disclosure;

FIG. 2 is a cross-sectional view of the filter assembly of FIG. 1, thecross-section being taken along the line 2-2 of FIG. 1;

FIG. 3 is an enlarged cross-sectional view of a portion of the filterassembly of FIG. 2;

FIG. 4 is an exploded, perspective view of the filter assembly of FIG.1;

FIG. 5 is a cross-sectional view one step in making the housing for thefilter assembly of FIGS. 1-4;

FIG. 6 is a cross-sectional view of a portion of the filter housing inanother step of making the housing used in the assembly of FIG. 1;

FIG. 7 is a cross-sectional view of the portion of the housing of FIG. 6in another step of making the housing used in the assembly of FIG. 1;

FIG. 8 is a cross-sectional view of the portion of the housing of FIGS.6 and 7 in another step of making the housing used in the assembly ofFIG. 1;

FIG. 9 is a graph showing results of testing including a can, interfacering secured to the can, and the wall of the interface ring being angledbetween first and second ends at 8.5°;

FIG. 10 is a graph showing results of testing with a filter housing madein accordance with principles of this disclosure;

FIG. 11 is a photograph of a fixture for a static burst test with a canhaving a wall of the interface ring being angled between first andsecond ends at 8.5°;

FIG. 12 is a photograph of the can of FIG. 11 after the static bursttest;

FIG. 13 is a photograph of a can with an 8.5° interface ring in anormal, intact position, before burst testing;

FIG. 14 is a photograph of the can of FIG. 13 after burst testing;

FIG. 15 is a photograph of 3 cans after burst testing; and

FIG. 16 is a photograph of 2 cans after burst testing.

DETAILED DESCRIPTION

The arrangement of FIGS. 1-8

A filter assembly is illustrated in FIG. 1 at reference numeral 10. Thefilter assembly 10 includes a filter cartridge 12 releasably connectedto a filter head 14. The filter cartridge 12 can be either a spin-oncartridge 12 or a bowl-cartridge filter 12.

The filter cartridge 12 includes a housing 16 and a filter element 18held by the housing 16. In a spin-on cartridge 12, the element 18 is notremovable and replaceable from the housing. Rather, when the cartridge12 needs servicing, the entire housing and element is disposed of andreplaced with a new cartridge 12 having a new housing and element. In abowl-cartridge filter, the element 18 is removable and replaceable fromthe housing 16. When the cartridge 12 needs servicing, the old element12 is removed and replaced with a new element 18. Both types of filtercartridges 12 in the form of a spin-on or bowl-cartridge filter areapplicable to the principles of use herein.

The filter element 18 is illustrated herein as being a tubular sectionof filter media 20. In many preferred implementations, the media 20 canbe in the form of a cylinder, in which the media 20 encloses an interiorvolume 22. The media 20 can be many different types of filter media,depending on what type of fluid is being filtered. For example, themedia 20 can be pleated media. The media 20 can be cellulose, synthetic,or blends of cellulose and synthetic. The media 20 can be treated withfine fibers. The media 20 can also be multiple layers of media,including one or more layers of depth media. Many variations arepossible.

The media 20 has opposite first and second ends 24, 26. In theembodiment shown, the first end 24 is secured to a first end cap 28. Thefirst end cap 28 is closed and is not in communication with the interiorvolume 22.

The second end 26 is secured to a second end cap 30. The second end cap30 is shown as being an open end cap that is in communication with theinterior volume 22. In FIG. 2, an opening 32 of the second end cap 30receives a spud 34 from the filter head 14, which allows the spud 34 toproject within the interior volume 22 and be surrounded by the media 20.A seal member 36 is between the second end cap 30 and the spud 34 toform a seal between and against the second end cap 30 and an outersurface 40 of the spud 34.

The filter head 14 includes a base 42 defining flow arrangements 44. Afirst flow arrangement is at 46, while a second flow arrangement is at48. Depending on the desired flow of fluid through the filter element18, the first flow arrangement 46 can be either an inlet or an outlet,and the second flow arrangement 48 can be either an outlet or an inlet.In a forward flow system, in which flow through the filter element isdesired to flow from outside of the media 20 to the interior volume 22,the first flow arrangement 46 will be an inlet arrangement 50, while thesecond flow arrangement 48 will be an outlet arrangement 52. It shouldbe understood that in reverse-flow conditions, the second flowarrangement 48 will be inlet arrangement, while the first flowarrangement 46 will be outlet arrangement.

The base 42 includes an outer wall 54. The outer wall 54 is constructedand arranged to releasably attach to the filter cartridge 12. In thisembodiment, the outer wall 54 includes threads 56.

In operation, fluid to be filtered, when a forward flow system is setup, will be directed to the filter head 14 through the inlet arrangement50. From there, the fluid will enter the unfiltered fluid volume 58,which is between the housing 16 and the outer periphery of the media 20.The fluid will then flow through the media 20 and into the interiorvolume 22. The media 20 will filter or remove at least some impuritiesfrom the fluid. The filtered fluid in the interior volume 22 will thenexit the filter cartridge by flowing into the aperture 60 of the spud 34and into the outlet arrangement 52. The filtered fluid will then exitthe filter head 14.

In accordance with principles of this disclosure, the housing 16includes a can 62. The can 62 includes a wall 64 surrounding an interiorvolume 66 and an open mouth 68 (FIG. 4). The can wall 64 has an innerwall surface 70 and an opposite outer wall surface 72. The inner wallsurface 70 is in communication with the interior volume 66 of the can62.

In the example embodiment shown, the can 62 has a closed end 74 oppositeof the mouth 68. The closed end 74 is illustrated as dome-shaped, but itcan also be flat.

In many preferred embodiments, the can 62 will be made of metal, such aspressed steel.

In other embodiments, the can 62 can be made from spun or press formedmetal. Metals that can be spun or pressed include aluminum and alloys,including 1100, 2024, 3002, 3003, 5052, 6061; cold/hot rolledSteel—galvanized; copper, brass, bronze & muntz metal; hastelloy;inconel; kovar; stainless steel: type 304(L), 316(L), 310, 321, 347;titanium; and niobium.

The wall 64 of the can 62 will have a cross-sectional thickness of atleast 0.7 mm and not greater than 2.5 mm, for example about 0.6-1.5 mm;and in some example embodiments about 1.1 mm. For wall thicknesses ofabout 1.1 mm, the burst pressure will be at least 1700 psig by splittinglongitudinally along a length of the can wall 64. For wall thicknessesgreater than 1.1 mm, it is expected that there would be a burst pressurehigher than 1700 psig; for wall thicknesses less than 1.1 mm, it isexpected that there would be a burst pressure less than 1700 psig.

The housing 16 further includes an interface ring 76. The interface ring76 can be secured to the can 62 adjacent to the open mouth 68.

The interface ring 76 comprises a ring wall 78 with first and secondopposite ends 80, 82. The ring wall 78 has an outer ring surface 84 andan inner ring surface 86 between the first end 80 and second end 82.

In this embodiment, the inner ring surface 86 includes a connectionmechanism for releasably connecting the housing 16 to the filter head14. In the example shown, the inner ring surface 86 has threads 88 forreleasably attaching to the threads 56 of the filter head 14. Otherembodiments are possible. For example, instead of having a threadedconnection, the connection mechanism could be a bayonet fitting or thelike.

In the embodiment shown, the outer ring surface 84 is against the innerwall surface 70 of the can 62. As explained further, there are noadditional seal members, adhesive, or other structure or materialsbetween the outer ring surface 84 and the inner wall surface 70 the can62.

The ring wall 78 is angled at a non-zero and non-perpendicular anglebetween a line 77 parallel to a central axis 79 (FIG. 5) of theinterface ring 76 and a portion 81 of the outer ring surface 84 betweenfirst end 80 and second end 82. This angle is shown in FIG. 3 atreference numeral 92. The angle 92 is preferably greater than one degreeand less than 6 degrees.

By having the ring wall 78 angled at angle 92 when the interface ring 76is inserted into the can 62, the can 62 will be stretched at stretchedsection 93, adjacent to the mouth 68. The stretched section 93 resultsin strengthening the can 62. Although no particular theory is asserted,it could be that stretching the can 62 is a form of work hardening, toincrease the strength. The result is that the failure point of thehousing can be along the can at the hoop stress point; that is, thefilter cartridge 12 can split longitudinally along the can wall 64 in adirection between the closed end 74 and the mouth 68, shownschematically in FIG. 1 at 95. When a filter splits longitudinally downthe length of the can wall 64, it means the total yield strength of theraw materials of the filter can has been achieved. This is contrastedwith a failure resulting from plastic deformation of the can 62, forexample, when the can 62 uncurls from the interface ring 76.

The angle 92 is selected to result in having the wall 64 of the canstretched to increase the strength but not to the extent that the wall64 of the can weakens.

In one or more embodiments, the ring wall 78 is angled at angle 92 lessthan 5 degrees.

In one or more embodiments, there have been advantages from having thering wall 78 be angled at angle 92 at least 1.5 degrees.

In one or more embodiments, the ring wall 78 has advantages when angledat angle 92 less than 4 degrees.

In one or more embodiments, advantages result when the ring wall 78 isangled at angle 92 between 1.5 degrees and 4 degrees.

The ring wall 78 has a cross-sectional thickness of at least 2 mm; insome embodiments, 3-10 mm, for example 6-9 mm, and in preferredimplementations, not greater than 8 mm. The thicker the ring wall 78,the smaller the filter element that can be installed and the moreexpensive it is to manufacture.

The housing 16 includes a seal member 94. The seal member 94 forms aseal 96 with the filter head 14, when the housing 16 is operablyconnected to the filter head 14.

The seal member 94 is adjacent to the open mouth 68 of the housing 16.In FIG. 2, it can be seen how the seal member 94 is formed between andagainst the housing 16 and the base 42 of the filter head 14. The sealmember 94 can be a gasket, or o-ring, or other similar constructions.The seal member 94 may be made of a rubber-like material, although othermaterials are possible.

The interface ring 76, in preferred embodiments, has a beveled surface98. The beveled surface 98 can extend from the first end 80 of theinterface ring 76 at the outer ring surface 84 and extend to the innerring surface 86.

Attention is directed to FIG. 3. The beveled surface 98 is shown at anangle 102. The angle 102 is for helping to keep the can 62 secured tothe interface ring 76. The angle 102 of the beveled surface 98 ispreferably at least 40 degrees.

In one or more embodiments, the beveled surface 98 has angle 102 that isno greater than 70 degrees.

In one or more embodiments, the angle 102 of the beveled surface 98 willbe between 40 degrees and 70 degrees.

Still in reference to FIG. 3, the can 62 has a section 104 that isfolded over the interface ring 76 at the open mouth 68. This folded oversection 104 forms a J-seam 105 (FIG. 8) with the interface ring 76.

In preferred implementations, the can 62 has section 104 folded over andagainst the beveled surface 98. As can be seen in FIG. 3, in thisembodiment, the seal member 94 is between and against the section 104and the filter head 14.

In the example shown, the seal member 94 is along the outer wall 54 ofthe head 14 and adjacent to the threads 56. The seal member 94 formsseal 96 between and against the folded section 104 of the can 62 and theouter wall 54 of the filter head 14.

It should be noted that the housing 16 and the filter cartridge 12 isseal member-free between the interface ring 76 and the can wall 64.

Preferably, the outer ring surface 84 is against the inner wall surface70 of the can 62 in direct contact and attached without any additionalattachment mechanism, such as adhesive, welding, etc. Preferably, thearea between the outer ring surface 84 and the inner wall surface 70 ofthe can 62 is adhesive-free.

In one or more embodiments, the interface ring 76 is secured to the can62 free of any welds.

The interface ring 76, once inserted in the can 62 to stretch the can62, will be self-supporting within the can 62; that is, there is nothingelse in the can 62 that is needed to hold the interface ring 76 inplace. This can be accomplished by an interference fit between the outerring surface 84 and the inner wall surface 70 of the can. As used hereinan interference fit, also known as a press fit or friction fit, means afastening between two parts which is achieved by friction after theparts are pushed together, rather than by any other means of fastening.

In one or more example embodiments, the can wall 64 is free of anyshoulders, ridges, or radially inward extending bumps at the second end82 of the ring wall 78. None are needed to support the interface ring76. There can be many variations.

In preferred embodiments, the can wall 64 is completely shoulder-free.

The folded section 104 is preferably the only fold that is in the can62. In one or more embodiments, the can 62 has no more than a singlefold, being depicted at folded section 104.

Methods of operating the filter assembly 10 should be apparent from theabove. In one method, there is a step of providing a filter assembly 10with an inlet arrangement, outlet arrangement, and filter media. Forexample, the filter assembly 10 can be provided including cartridge 12with housing 16 and filter head 14. The filter head 14 has inletarrangement 50, outlet arrangement 52, and filter media 20.

The method of filtering can include the step of directing fluid into thehousing 16 through the inlet arrangement 50; filtering the fluid bydirecting the fluid through the media 20; and then directing the fluidout of the housing 16 through the outlet arrangement 52 of the filterhead 14.

The method of filtering will include using filter housing 16, asvariously characterized above, in which the burst pressure of the filterhousing 16 is at least 1700 psig.

The filter assembly 10 can be made using only press tools, which hasadvantages in that the assembly 10 does not require sophisticatedequipment and can be assembled almost anywhere in the world. Examplemethods of making housing 16 for a filter cartridge 12 is shown in FIGS.5-8.

In one example method, there is a step of providing can 62 having wall64 surrounding interior volume 66 and an open mouth 68. The open mouth68 is surrounded a rim 106. The can wall 64 has inner wall surface 70 incommunication with the interior volume 66.

FIG. 5 shows the can 62 and interface ring 76 prior to inserting theinterface ring 76. The can 62 is cylindrical at the mouth 68, and it isnot stretched prior to insertion of the interface ring 76.

The method can include pressing interface ring 76 into the interiorvolume 66 of the can 62 through the open mouth 68. The interface ring 76has ring wall 78 with first and second opposite ends 80, 82, an outerring surface 84, and inner ring surface 86. The inner ring surface 86 isthreaded at 88. The outer ring surface 84 is against the inner wall 70of the can 62. The ring wall 78 is angled at angle 92 which is greaterthan 1 degree and less than 6 degrees.

FIG. 6 shows the interface ring 76 inserted through the mouth 68 of thecan 62, which stretches the wall 64 of the can 62 to form stretchedsection 93. The stretched section 93 will be stretched from the mouth 68along the can call 64 for the length of the interface ring 76 at thesame angle 92 (FIG. 3) of the interface ring 76 between the first andsecond ends 80, 82.

The method includes a step of pressing the rim 106 of the can 62 againstthe first end 80 of the interface ring 76 to fold the can 62 against theinterface ring 76.

The step of pressing the rim 106 against the first end 80 of theinterface ring 76 includes, as shown in FIG. 6, bending the section 104of the can 62 first to a 45 degree angle.

In FIG. 7, the section 104 of the can 62 is bent to a 90 degree angle.

FIG. 8 illustrates the section 104 of the can 62 being bent to conformto the first end 80 of the interface ring 76.

In preferred implementations, the first end 80 will include the beveledsurface 98, so that the section 104 is pressed against the beveledsurface 98.

The method of making can include adding no more than a single fold ofthe can 62, the fold being at section 104 against the first end 80 ofthe interface ring 76.

The method can include orienting seal member 94 on the folded rim 106along section 104 of the can 62.

The housing 16 can be made to have any of the various features ascharacterized above including, for example: the housing being sealmember-free between the interface ring and can wall; the interface ringbeing self-supporting within the can; the ring wall angle 92 being lessthan 5 degrees; the ring wall angle 92 being at least 1.5 degrees; thering wall angle 92 being less than 4 degrees; the ring wall angle 92being angled between 1.5 degrees and 4 degrees; the interface ring beingsecured to the can without the use of any welds; the can being made ofmetal, such as pressed steel; and the can wall having a cross sectionalthickness of 0.6-1.5 mm, for example, about 1.1 mm.

EXAMPLES

Three different static burst tests using oil as the pressure fluid wereconducted on filters with a can 62 having a J seam 105 including a wallof the interface ring 76 being angled between first end 80 and secondend 82 at 8.5° (abbreviated herein as “the 8.5° can”) with the resultsshown in FIG. 9. Each filter used a can wall having a thickness of about1.1 mm and made from pressed steel. All three tests had very similarresults. For example, in all three tests: seal integrity was broken by500 to 600 psig; almost complete seal failure was observed by 800 psig;and J seam uncurling and interface ring shifting was observed at 1,400to 1,500 psig. Failures due to can (housing) wall splitting were notobserved in any of the tests. Failure by means other than can wallsplitting suggests the total yield strength of the raw materials of thecan wall was not achieved—rather, failure occurred because of leakingfollowed by the lip of the can uncurling from the interface ring.

FIG. 9 shows a graph showing results of a burst tests using the filterhousing described above having the 8.5° can. In the FIG. 9 graph,psid=psig because the differential pressures were the internal housingpressure and atmosphere. Using oil as the pressure median the firstcircle 200 on the static bust test pressure curve indicates where theseal starts to fail (500-600 psig); the second circle 202 shows thepressure (800 psig) that the seal fails almost completely; and the thirdcircle 204 highlights the pressure, about 1,500 psig, that the J Seamuncurls resulting in complete product failure.

FIG. 11 is a photograph of a fixture for a static burst test with an8.5° can. The can in FIG. 11 is shown before the burst test. FIG. 12 isa photo of the can of FIG. 11 after the burst test. In FIG. 12, failurecan be seen in the form of the J-seam uncurling and the interface ringextruding from the can.

The domed end of tested metal housings were observed. See FIG. 15. Themaximum deformation observed with the 8.5 degree can was compared to thedomed end of a 3 degree can. The 3° can was a filter housing madeidentical to the 8.5° can (identical materials and wall thickness), withthe only difference being the interface ring 76 is angled between firstend 80 and second end 82 at 3° instead of 8.5°. In FIG. 15, theleft-most can shows the domed end of the can before the static bursttest. The middle can shows an 8.5° can after the burst test, and theright can shows a 3° can after the burst test. The deformation in thedomed end that was observed with a static burst test on the 3 degree canwas greater than what was observed with the 8.5 degree can. Thissuggests that the internal metal housing pressure was much greater withthe 3 degree ring versus the 8.5 degree ring.

FIG. 16 is a photograph comprising the 8.5° can (left can) after theburst test to the 3° can (right can) after the burst test. The 8.5° canshows catastrophic failure due to an extruded interface ring. The 3° canshows failure by a longitudinal split along the can wall. The J seamfailure for both the cans was about 1500 psig, and the internal pressureto form a longitudinal split along the can wall for this can materialand wall thickness was about 1700 psig.

FIG. 10 is a graph showing burst test results of a filter made accordingto principles of this disclosure, having a 3 degree press fit interfacering and a can wall having a thickness of about 1.1 mm and made frompressed steel. There was J seam uncurling at about 1500 psig, and afailure by longitudinal split along the can wall over 1700 psig, indeedin excess of 1800 psig.

In comparing the 8.5 degree interface ring versus the 3 degree interfacering of the present disclosure, the following observations can be made:Using the 3 degree press fit ring of the present disclosure, there wasno seal leakage until failure due to the J-seam uncurling at around1,500 psig (same as the 8.5 degree design). The 3 degree press fitinterface ring of the present disclosure burst via longitudinal splitalong the housing at an internal pressure of greater than 1,700 psig,indeed greater than 1800 psig. The 8.5° cans leaked at internalpressures starting at 500 psig and were not able to maintain an internalpressure great enough to achieve a burst metal housing via longitudinalsplit.

Evidence of the ability to achieve a greater maintained internalpressure for a product constructed using the 3 degree press fitinterface ring of the present disclosure was demonstrated through thegreater extension of the closed dome end and burst metal failures. Theseobservations show a leak free design until failure better at a 3 degreepress fit design when compare to the 8.5 degree press fit design.

The above represents example principles. Many embodiments can be madeapplying these principles.

What is claimed is:
 1. A filter cartridge comprising: (a) a housingincluding, (i) a can having a wall surrounding an interior volume and anopen mouth; the can wall having an inner wall surface in communicationwith the interior volume; (ii) an interface ring secured to the canadjacent to the open mouth and having a ring wall; (iii) the ring wallbeing at an angle of greater than 1° and less than 6°; and (b) a filterelement operably mounted in the interior volume of the can.
 2. A filtercartridge according to claim 1 wherein: (a) the interface ring has abeveled surface; and (b) the can has a section folded over and againstthe beveled surface.
 3. A filter cartridge according to claim 1 furthercomprising: (a) a seal member against the folded section of the can. 4.A filter cartridge according to claim 1 wherein: (a) the housing isseal-member free between the interface ring and the can wall.
 5. Afilter cartridge according to claim 2 wherein: (a) the beveled surfacehas an angle of at least 40°.
 6. A filter cartridge according to claim 2wherein: (a) the beveled surface has an angle no greater than 70°.
 7. Afilter cartridge according claim 1 wherein: (a) the can has a closed endopposite of the mouth.
 8. A filter cartridge according to claim 1wherein: (a) the ring wall is at an angle of less than 5°.
 9. A filtercartridge according to claim 1 wherein: (a) the ring wall is at an angleof at least 1.5°.
 10. A filter cartridge according to claim 1 wherein:(a) the ring wall is at an angle of less than 4°.
 11. A filter cartridgeaccording to claim 1 wherein: (a) the can has no more than a singlefold.
 12. A filter cartridge according claim 1 wherein: (a) the ringwall is angled between 1.5° and 4°.
 13. A filter cartridge according toclaim 1 wherein: (a) the interface ring is secured to the can weld-free.14. A filter cartridge according to claim 1 wherein: (a) the can wallhas a cross-sectional thickness of between 0.8 and 1.5 mm.
 15. A filtercartridge according to claim 1 wherein: (a) the can is made of pressedsteel.
 16. A filter cartridge according to claim 1 wherein: (a) an innerring surface of the interface ring is threaded.
 17. A filter cartridgeaccording to claim 1 wherein: (a) the filter element is non-removablymounted in the housing.
 18. A filter cartridge according to claim 1wherein: (a) the filter element is removable and replaceable in thehousing.
 19. A filter cartridge according to claim 1 wherein: (a) thehousing is constructed and arranged to have a burst pressure of at least1700 psig.
 20. A filter assembly comprising: (a) a filter head having athreaded connection portion; and (b) a filter cartridge according toclaim 1 threadably attached by the interface ring to the threadedconnection portion.